Arcuate surface grinding device



y 1969 KIYOSHI HAJIKANO 3,442,054

ARCUATE SURFACE GRINDING DEVICE Sheet Filed Oct. 21, 1966 FIG.2.

May 6, 1969 KIYOSHI HAJIKANO 3,442,054 ARCUATE SURFACE GRINDING DEVICE Filed Oct. 21, 1966 United States Patent Office 40/6 Int. Cl. B24b 7/00, 9/00, /00

US. CI. 51-80 5 "Claims ABSTRACT OF THE DISCLOSURE A grinding device in which a pair of parallel driving shafts supports respective pairs of spaced roll supporting wheels carrying a plurality of grinding rolls arranged in cylindrical array around the common axis of each pair of roll supporting wheels, the grinding rolls being inclinably supported at both ends by said roll supporting wheels, and being adjustable in inclination by increasing or decreasing the distance between the roll supporting wheels in each pair, the arrangement being such that the spacing of the wheels of one pair is increased while that of the other pair is decreased, whereby the inclination of the rolls are varied in opposite directions and a workpiece inserted between the rolls will be ground to different curvature on opposite sides thereof by the respective arrays of rolls.

In grinding a cylindrical body which does not have a circular cross section but has, for example, somewhat flattened and arcuate surfaces, it has hitherto been the practice to grind the body first by a grinder to form a circular cross section and then to finish it to a desired contour either by a profiling machine or the like having a bit or grinding wheel, or by drawing. The process has therefore involved great difiiculties.

An object of the present invention is to provide a device to eliminate these difficulties.

Now the present invention will be described more specifically with respect to an embodiment thereof shown in the accompanying drawings.

FIG. 1 is a front view of an ent invention;

FIG. 2 is a side view of the embodiment, partially in vertical section;

FIG. 3 is a side view of a part of the above embodiment, partially in vertical section;

FIG. 4 is a side view of a roll supporting wheel;

FIG. 5 is a vertical sectional view of a part of roll supporting assembly; and

FIG. 6 is a diagram illustrating the principle of the invention.

A frame 1 supports rotatably a pair of driving shafts 2 arranged in parallel and vertically spaced relation. Each driving shaft is provided with a pair of roll supporting wheels 3, 4 suitably spaced from each other and having a compression spring 5 interposed therebetween. Each of the roll supporting wheels 3, 4 supports a plurality (for example twelve) of bearings 6 having a spherical inner contour. The bearings are arranged in a circle, the center of which is on the axis of the respective wheel. Be tween the roll supporting Wheels 3, 4 of each pair, a plurality (for example twelve) of grinding rolls 7 are arranged in cylindrical array around the common axis of the wheels. Each grinding roll 7 consists of a spindle 8 and a grinding material 9 mounted on the spindle, which material is e.g. of diamond baked with metal bond onto the spindle. Necks 10 at both ends of each grinding roll have ball-shaped bearing elements 11 which are supported by corresponding bearings 6. The grinding rolls 7 are supported so as to be inclined relative to the longiembodiment of the pres- 3,442,054 Patented May 6, 1969 tudinal axis of the spindle by the roll supporting wheels 3, 4. To each of the roll supporting wheels 3, 4, a supporting cover 12 is secured with a suitable number of setscrews 13. The roll supporting wheels 3 on one (left) side are rotatably and slidably supported by the driving shafts, while the roll supporting wheels 4 on the other (right) side are slidably supported by splined portions 14 of the driving shafts 2. Outside the roll supporting wheels 3, 4, thrust bearings 15 are fitted onto the driving shafts 2, and beyond the bearings there are disposed racks 16 parallel to the longitudinal axis, each rack being slidably fitted in the frame 1. The racks 16 on both (left and right) sides have teeth 17 facing opposite each other, and are provided with pinions 18 which engage respective pairs of teeth. Spindles 19 of the pinions 18 are rotatably supported by the frame 1, and are equipped with handles 20 and suitable means (not shown) for stopping the rotation thereof.

When the driving shafts 2 are driven, the right roll supporting wheels 4 revolve and hence the left roll supporting wheels 3 also revolve simultaneously. When the left and right handles 20 are turned in opposite directions through the same angles, the upper and lower racks 16 connected therewith slide in directions opposite each other, thereby moving the roll supporting wheels 3, 4 through the thrust bearings 15 in the axial direction. When the distance between the roll supporting wheels 3, 4 of each pair is decreased, the wheels are resisted by the resilient force of the compression spring 5, while an increase in the distance depends on the force of the spring. In proportion to the increase or decrease of the distances between the respective roll supporting Wheels 3, 4, the inclinations of the groups of grinding rolls 7 are changed. If the grinding rolls 7 are indicated by full lines 1,-1', 2-2, 3-3 12-12 as shown in FIG. 6, then the matrix lines of the grinding rolls 7 form together a hyperboloid of revolution as indicated by dotted lines in the same figure.

When the groups of grinding rolls 7 in tilted position with suitably selected inclination are revolved around the driving shafts 2 and a workpiece is introduced between a pair of the groups of grinding rolls which constitute a pair of rotational hyperboloid surfaces, the work can be ground by the grinding faces of the grinding rolls. As already stated, the contours of the hyperboloid surfaces of rotation can be varied by suitably turning the left and right handles 20 and hence workpieces can be ground so as to form many different arcuate surfaces.

When positioned as shown in FIG. 1, the hyperboloid of revolution formed by the upper group of grinding rolls and that formed by the lower group of grinding rolls are of similar shape. Accordingly, in this case, the workpiece can be ground into arcuate surfaces of similar radius of curvature on upper and lower surfaces. When the distances between the upper and lower roll supporting wheels 3, 4 are extended or reduced, the hyperboloid of revolution formed by the upper group of grinding rolls and that formed by the lower group of grinding rolls are not of similar shape. Accordingly, in this case the workpiece can be ground with arcuate surfaces of different radii of curvature, on the upper and lower surfaces.

What is claimed is:

1. A device for grinding surfaces of different curvature on a workpiece, said device comprising a pair of parallel drive shafts, a pair of spaced roll supporting wheels on each drive shaft, the wheels on one side being rotatable and slidable on the respective drive shaft while the wheels on the other side are rotatable with the respective drive shaft and slidable thereon, a plurality of grinding rolls arranged in cylindrical array around each shaft, the array of rolls on the parallel drive shafts defining a space therebetween in which a workpiece can be inserted and ground on opposite surfaces by the rolls associated with each shaft, each roll having opposite ends pivotably supported in respective wheels, and means for varying the distance between the wheels of each pair conjointly thereby to tilt the rolls supported by such wheels and vary the curvature of the surface defined by the rolls.

2. A device as claimed in claim 1, wherein said means for varying the distance between the wheels of each pair comprises means coupling the wheels of both pairs such that the wheels of one pair are moved towards one another while the wheels of the other pair are moved away from one another.

3. A device as claimed in claim 2, wherein said means coupling the wheels comprises a rack for each wheel, and 1 a pinion engaging racks of wheels of different drive shafts.

4. A device as claimed in claim 2 comprising a compression spring interposed between the wheels of each shaft.

5. A device as claimed in claim 1, wherein each grinding roll is a rigid cylindrical element.

References Cited FOREIGN PATENTS 1/1960 Canada.

ROBERT C. RIORDON, Primary Examiner.

5 D. G. KELLY, Assistant Examiner.

US. Cl. X.R. 

